Clinical pharmacology and therapeutics
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Clin. Pharmacol. Ther. · Oct 2003
Clinical TrialCisapride disposition in neonates and infants: in vivo reflection of cytochrome P450 3A4 ontogeny.
Cisapride, a prokinetic agent and substrate for cytochrome P450 (CYP) 3A4, has been used to treat neonates and infants with feeding intolerance and apnea or bradycardia associated with gastroesophageal reflux. At age 1 month, CYP3A4 activity has been reported to be only 30% to 40% of adult activity. This known developmental delay in the expression of CYP3A4 prompted us to conduct a classical open-label pharmacokinetic study of cisapride in neonates and young infants. ⋯ (1) In neonates and infants, cisapride absorption and metabolism to its primary metabolite, norcisapride, were developmentally dependent; (2) approximately 99% of cisapride CL/F in neonates and young infants was nonrenal in nature; (3) CL/F of cisapride in neonates and infants noted in this study was reduced compared with data from older children and adults, likely as a result of developmental reductions in CYP3A4 activity; (4) as reflected by the correlation between postconceptional age and lambda(z), a rapid increase in total CYP3A4 activity occurs in the first 3 months of life.
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Clin. Pharmacol. Ther. · Oct 2003
Clinical and economic consequences of reference pricing for dihydropyridine calcium channel blockers.
Reference pricing is a medication cost-sharing policy that fully covers medications which are less expensive than a standard reference price and requires patients to pay the extra cost of higher-priced drugs in a class of therapeutically substitutable drugs. Little information exists on the clinical and economic consequences. We analyzed changes in drug utilization, physician visits, hospitalizations, long-term care admissions, and expenditures after the introduction of reference pricing for dihydropyridine calcium channel blockers (CCBs) among patients aged 65 years or older in British Columbia, Canada. ⋯ Reference pricing as implemented in British Columbia may be a model for successful pharmaceutical cost-containment without adversely affecting patients or cost-shifting.